One provision outlawed designer drugs such as synthetic marijuana, "spice" and "herbal incense" as well as the bath salts that were implicated in a recent "cannibal" attack on a homeless person in Miami.

U.S. Senator Jeff Merkley, D-Ore, hailed the Senate version of the bill late last month, saying he'd successfully inserted provisions ensuring better performance tracking to improve medical device safety. The provisions mirrored a bill authored by Merkley, who serves on the Senate Health, Education, Labor and Pensions Committee.

But the consumer advocacy group Public Citizen, founded by Ralph Nader, contends the compromise bill means an overall weakening of drug and medical device safety.

Asked for comment, Merkley's office said he hasn't reviewed the details of the new bill, but called it good news that it still includes the medical device safety measures he inserted, as well as expanded FDA authority to address drug shortages.